1. Field
The present disclosure relates generally to cooling systems and, in particular, to a method and apparatus for cooling a heat source. Still more particularly, the present disclosure relates to a method and apparatus for cooling a heat source using a phase change material in a cooling system.
2. Background
Various components in an aircraft may generate heat and require cooling. For example, without limitation, line replaceable units and other components in an aircraft network may require cooling to maintain those components at an appropriate operating temperature. These types of components may generate heat constantly.
Other components in the aircraft may generate heat on a non-constant basis. These types of components may generate heat based on an event that may be periodic or non-periodic. For example, without limitation, directed energy weapons that may be carried as a payload may generate heat when those weapons are used. The heat generated may be a large amount of heat over a short period of time. With these and other components, it may be desirable to provide required cooling for a lowest possible weight.
A number of conventional heat-exchangers exist that may be used as phase change heat exchangers. A shell and tube heat-exchanger may be an example, which is in widespread use for a wide variety of working fluids and in a large range of sizes owing to its scalability. Although this type of cooling system may be low cost, the weight and size of a conventional shell-and-tube heat-exchanger may limit its feasibility for airborne applications in which low mass and/or weight may be important. Using this type of heat-exchanger may increase the weight of the aircraft to an unacceptable level. Further, the required weight reduction may only be achieved by reducing the weight of other components, such as the payload.
A shell-and-tube heat exchanger may not provide effective thermal transfer to and from a phase change material (PCM) which may be of relatively low thermal conductivity, which may be the case for many aqueous and non-aqueous materials that may be conveniently used as a phase change material. These limitations may be addressed by the use of materials such as reticulated open-cell foam metal, but incorporation into a shell-and-tube topology may be difficult. More advantageous geometries for foam metal may be possible, but the foam metal medium may represent a mass addition to the overall system.
Therefore, it would be advantageous to have a method and apparatus that overcomes one or more of the issues described above.